A new generation of cellulosic appeared in the market in December 1992 when a commercial plant in the USA started to make a lyocell staple fibre, based largely on European man-made fibre industry research. Subsequently, two European production plants have opened.
The process used to make lyocell fibres is a solvent spinning process. The cellulose is directly dissolved in the solvent N-methylmorpholine n-oxide (NMMO) containing just the right amount of water. The solution is then filtered and spun through spinnerets to make the filaments, which are spun into water. The NMMO solvent is recovered from this aqueous solution and reused.
Properties and End-Uses
The lyocell fibres, like other cellulosics, are moisture absorbent and biodegradable. They have a dry strength higher than other cellulosics and approaching that of polyester. They also retain 85% of their strength when wet. Under certain conditions lyocell fibres fibrillate which enables fabrics to be developed with interesting aesthetics. Non- fibrillating versions are also available. Lyocell fibres are mostly used for apparel fabrics, especially outerwear, but it has been shown that, due to the fibrillating property some very interesting nonwoven fabrics can be made as well.